1. Field of the Invention
The present invention relates generally to a semiconductor device having a relief circuit for relieving a defective portion and, more particularly, to one used in relieving by use of a fuse element.
2. Description of the Related Art
A semiconductor device has conventionally been provided with a relief circuit so that a defect, if any in the semiconductor circuit, may be replaced by the relief circuit.
A configuration of the conventional relief circuit is shown in FIG. 1. In this configuration there are provided a relief portion 102 to relieve a relief-subject section 101, and a fuse element 103, which corresponds to this relief portion 102. The fuse element 103 stores therein information to indicate, when a relief-subject section 101 is replaced by a relief portion 102, that the relief portion 102 is being used in replacement, and information to specify the relief-subject section 101 thus replaced.
Conventionally, however, only one fuse element 103 corresponds to each relief portion 102, so that a defect in the relief-subject section 101 can be replaced by the relief portion 102 only by using a relief method given by that fuse element 103. Therefore, there is a problem that a defect can be replaced by the relief portion 102 only in one of a plurality of evaluation steps.
Furthermore, it has conventionally been impossible to confirm, by an evaluation apparatus (tester), whether a defect is already replaced by the relief portion 102. That is, before replacement with the relief portion 102 in accordance with an evaluation result in an evaluation step, it is impossible to directly confirm through the evaluation apparatus whether the relief portion 102 is already used. Therefore, once a defect is replaced by the relief portion 102 in a semiconductor device, another defect, if any, that needs to be replaced by the relief portion 102 in accordance with an evaluation result, cannot easily be done so because the fuse element 103 which has been used in the first replacement with the relief portion 102 cannot be confirmed, which is a problem (see FIG. 2).